A185622 Column 2 of triangular matrix T = A185620, which satisfies: T^3 - T^2 + I = SHIFT_LEFT(T).

1, 1, 5, 27, 173, 1330, 12134, 129359, 1587501, 22127494, 346245249, 6021401618, 115373290404, 2417393483696, 55028734386699, 1353170738090204, 35764709876549353, 1011496211524329699, 30490289594142366215

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Prog

 (PARI) {A185620(n, k)=local(A=Mat(1), B); for(m=1, n, B=A^3-A^2+A^0;
A=matrix(m+1, m+1); for(i=1, m+1, for(j=1, i, if(i<2|j==i, A[i, j]=1,
if(j==1, A[i, j]=1, A[i, j]=B[i-1, j-1]))))); return(A[n+1, k+1])}
/* Column 2: */ {a(n)=A185620(n+2, 2)}

Crossrefs

Cf. A185620, A185621, A185623.

Sequence in context: A109963 A201870 A091101 * A225309 A231091 A205774

Adjacent sequences: A185619 A185620 A185621 * A185623 A185624 A185625

Keyword

nonn

Author

Paul D. Hanna, Feb 01 2011

Status

approved